融合航迹和磁罗经信息的侧扫声呐瞬时航向修正

Instantaneous course repair of side-scan sonar combined by the information of track and magnetic heading

为了消除航向偏差引起的侧扫声呐成图几何畸变,提高侧扫声呐镶嵌成图的质量,本文充分考虑了航迹推估航向和磁罗经航向趋势的一致性、拖鱼磁罗经航向相较船体运动的滞后性、磁罗经偏差的不稳定性等航向数据特点,提出了一种利用航迹推估航向低频信息修正磁罗经瞬时航向的方法。该方法包括航向序列小波分析、峰谷匹配、磁罗经偏差修正模型构建等内容,并通过实测数据处理和应用验证了该方法的有效性,采用修正后的磁罗经航向进行条带图像编码镶嵌,目标形状完整、轮廓过渡自然,相邻条带共视目标特征一致性显著提高。本文工作对提高传统侧扫声呐成图质量、挖掘侧扫声呐图像定量分析潜力具有重要意义。

Course deviation is the main factor causing geometric distortion of side-scan sonar mapping.The course of shipborne compass recorded by traditional side-scan sonar system,the course of magnetic compass built in tow fish and the course estimated by track position are all difficult to meet the needs of high quality mosaic of side-scan sonar.This paper analyzes the influence of course deviation on side-scan sonar mapping,states the data characteristics,including the trend approximation between estimated course serial by track position and magnetic compass course serial,the hysteresis of tow fish magnetic compass course relative to vessel motion,the instability of magnetic compass course deviation.Then a method to correct instantaneous course of tow fish is proposed with the combination of magnetic compass information and low-frequency part of track position.The method includes wavelet analysis,peak-valley matching,course deviation correction model building.The application effectiveness of the method was verified in measured data processing test.Using corrected magnetic compass course to mosaic side-scan sonar image,we obtained high-quality sides-scan sonar mosaic image,the shape of the target is complete,the contour transition is natural,and the consistency of common target features of adjacent strips is significantly improved.This paper is of great significance to improve the quality of traditional side-scan sonar mapping and explore the potential of quantitative analysis of side-scan sonar images.